simply because we have free will.
the first time through the steps, my second step was my willingness to move forward with the other steps. step 2 didn't "make sense" or come to life until I worked past step 7. that is when I had a spiritual awakening or experience and the compulsion to drink was removed.....
everyone is different, but it took me 25 years to fully accept my alcoholism and be willing enough to work all of those steps, not slowly, I worked them slowly the second and third time through [by 8 months of sobriety I had worked them 3 times as my sponsor didn't let me stay stuck and I had to keep working those steps so I could really know how to guide another through those steps (I was sponsoring others at 8 months of sobriety to give back what was freely given to me)].
everyone works them differently